The present invention is directed to a device for the continuous tension-free treatment, such as drying, shrinking, finishing and the like, of textile fabric sheets so that the sheets can be lifted upwardly from a transport belt in at least one treatment zone by directing jets of air from below across the full width of the sheet. The fabric sheet is conveyed from one treatment zone to another in the transport direction in a gathered condition. At least one lower nozzle, extending transversely of the transporting direction, is located below the transport belt and is connected with a compressed air source. A closing member is arranged for selectively opening and closing the lower nozzle. A separating walls are positioned above the lower nozzle and above the transport belt and the walls extend transversely relative to the transport direction with adjacent separating walls defining a treatment zone. The lower jet extends in the upward direction and is inclined in the transporting direction by several degrees relative to the vertical. A perforated plate is located above the transport belt and is inclined upwardly relative to the transport belt in the transport direction. The perforated plate is located between two separating walls and the maximum distance between the transport belt and the perforated plate is in the range of 5 to 15 cm.
A device for the continuous treatment of textile fabric sheets is known, note German Patentschrift No. 26 44 309 corresponding to U.S. Pat. No. 4,121,311. In this known device, the fabric sheet is displaced upwardly into the air under the influence of pulse-like air jets only from below the fabric sheet whereby only the lateral extension is limited by two separating walls, but without any limitation to the height of displacement. As a result, tensile stresses are developed in the fabric sheet and they cannot be entirely eliminated when the sheet collapses after the flow of air is cut off. The shrinkage achieved in this device is completely insufficient.
A considerably improved version of this patented device is commercially available. The improvement involves the inclination of the lower nozzle in the transport direction by approximately 7.5.degree. to 15.degree. relative to the vertical. Further, a perforated plate is arranged inclined upwardly from the transport belt in the transport direction with the plate extending transversely across the transport direction. The perforated plate is located between separating walls and the maximum distance between the transport belt and the perforated plate is approximately 13 cm. The particular advantage in this improvement is that the upward displacement of the fabric sheet from the transport belt is limited so that tensile stresses are considerably reduced and the fabric sheet impacts with considerable force against the perforated plate or the separating walls and releases any tension stress in the fabric sheet.
Experience with this commercially available device has shown that the fabric sheets are stretched slightly during treatment. This stretching action may have several causes, for instance, the fabric sheet may be irregularly woven or knitted, it could have a velour surface, or the device may have been poorly adjusted.